Chicamacomico River examined for Pfiesteria Workers find menhaden with lesions in remote site southwest of Vienna

September 04, 1998|By Heather Dewar | Heather Dewar,SUN STAFF

The state's Pfiesteria rapid response team is investigating a stretch of the Chicamacomico River where workers found a small number of menhaden with fresh Pfiesteria piscicida-like lesions yesterday.

The site, near a ruined drawbridge on a slender, remote stretch of the river about four miles southwest of Vienna on the Lower Eastern Shore, was the scene of Maryland's fourth and last Pfiesteria-related fish kill of 1997. On Sept. 14, Gov. Parris N. Glendening ordered a six-mile stretch of the Chicamacomico closed after about 4,000 fish died of toxic Pfiesteria near the drawbridge.

Yesterday, biologists from the Department of Natural Resources found that 41 of the 163 menhaden netted at the drawbridge had fresh lesions like those caused by Pfiesteria, said DNR spokesman John Surrick. The proportion of lesioned fish falls within new guidelines for closing Pfiesteria-tainted waterways, but Surrick said state officials decided not to recommend a closure, because no fish kill occurred and the narrow stretch of the river is rarely used by fishermen or swimmers.

"The consensus was to go back out there tomorrow, see what we see and then make the call," Surrick said late yesterday, adding a chance exists that the river could be closed to the public later today "if we get numbers that are the same or worse."

The finding on the Chicamacomico was the latest evidence that Pfiesteria is active in Maryland waters, although at far lower levels than last summer, when the toxic microbe killed 35,000 or more fish on the Pocomoke, sickened some watermen and boaters, and forced the closure of four Lower Eastern Shore rivers.

This summer, no fish kills and only one confirmed outbreak of Pfiesteria have been reported -- an early August flare-up on Shiles Creek, a backwater of the Wicomico River. State officials decided not to close the creek, and the episode faded after about a week. Laboratory tests confirmed Pfiesteria piscicida was present in the creek, but at levels believed to be too low to cause a fish kill.

Experts are not sure why the lethal dinoflagellate has been less active, but they suspect the reason might be a shortage of menhaden. Large schools of the oily baitfish seem to trigger Pfiesteria outbreaks, but those schools have been sparse in Chesapeake Bay tributaries.

Phil Jones, DNR's director of resource management, said the relative lack of menhaden in local waters might be linked to a steady, Atlantic Coast-wide decline in the species' young. Biologists think environmental changes are to blame for that decline, but the exact causes aren't known, he said.